Why is my dog itchy?

Common Causes of Itching in Dogs

Itching in dogs is a symptom of an underlying issue; it is not a specific disease or illness. In medical terms, itching is referred to as “pruritus”. Affected dogs have the intense desire to scratch, bite, chew, or lick the affected area. Itching in dogs may be generalized or confined to a specific area of the body.

There is a very long list of potential causes of itching in dogs. Among the top and the most common causes are:

Parasites

When a dog is brought in for excessive itching and scratching, one of the first possible reasons that the vet will check for will be fleas. These bloodsucking parasites are very prolific, meaning they can reproduce very quickly and can make your pet’s life (and yours, too!) miserable. Flea bites can be very itchy, especially for dogs that are hypersensitive to a substance in flea saliva. Persistent scratching, licking, rubbing, and chewing can eventually cause hair loss and breaks on the skin surface. Without proper medical intervention, this can pave the way for secondary infections caused by bacteria and/or yeast.

In addition to your pet’s physical exam, you will also be asked about your pet’s health and skin history. To confirm the presence of a flea infestation, your vet will check your pet’s body for any fleas that may be present. However, there are cases in which fleas cannot be found on the dog’s body. But there is another tell-tale sign of flea infestation - flea dirt, which is the feces of fleas. Flea dirt looks like pepper granules and is composed of digested blood.

Ticks

Ticks are another group of external parasites that thrive on the blood of their hosts. Dogs can easily get ticks when wandering outdoors, particularly in grassy areas. When a tick attaches to the dog’s skin, it will suck the blood of the host. Once the tick is fully engorged, it will drop to the ground, leaving behind bite marks that appear as red, itchy marks on the dog’s skin. Ticks are also important carriers of several diseases, such as Lyme disease, Rocky Mountain Spotted Fever, etc. Some of these diseases are zoonotic, meaning they can affect humans, too.

One way to protect your pet against ticks is to make a habit of checking your pet’s body for ticks after each outdoor excursion. It’s important to remove the ticks before they can latch on and suck blood because once they feed for some time, they can be capable of transmitting any disease that they may be carrying.

Mites

Mites are very tiny parasites; they can only be seen under the microscope. Mites are not insects; they are related to spiders. These parasites cause mange in dogs, a skin problem that is characterized by skin itching, dry and scaly skin, and patchy areas of hair loss. The most common types of mange in dogs are sarcoptic mange and demodectic mange.

Sarcoptic mange is also called scabies and is caused by Sarcoptes sp. Affected dogs suffer from intense itching and discomfort, causing them to persistently scratch, chew, and lick itchy areas of the body. They may also rub their bodies against surfaces. All this skin scratching can eventually lead to hair loss, inflammation of the skin, and the formation of scabs. Sarcoptic mange can also infest humans.

Demodectic mange, also known as red mange, is caused by Demodex sp. Affected dogs experience hair loss, skin redness, scaling, and crusting.

Ear Mites

Ear mites are microscopic parasites that live on the ear passages of dogs. Affected pets are often seen shaking their heads and scratching their ears excessively. There may also be a build-up of ear wax and debris that can worsen the problem and create a favorable medium for bacterial and fungal infections.

Infections

Bacterial or fungal infections are possible reasons that your vet will look for if parasites have been ruled out as the cause of your pet’s itching. Skin infections are usually accompanied by skin scaling, oozing, distinct odor, and hair loss. Dogs with concurrent yeast and bacterial infections suffer from intense itching that causes them to engage in excessive scratching, chewing, licking, or rubbing of affected areas of the body. If an underlying infection is identified as the culprit, your vet may prescribe antibiotic therapy for several weeks.

Bacterial skin infections are important causes of hot spots (pyotraumatic dermatitis) which are very itchy.

The most common fungal skin infection in dogs is ringworm (dermatophytosis). Affected dogs have hairless patches with reddish scaly sores. Ringworm in dogs can be transmitted to other pets in the household and even to humans. Even if only one dog has ringworm, all pets in the house are presumed to be infected and should also be given antifungal treatment.

In some skin problems, itching may not be initially present but when there are secondary bacterial or yeast infections, itching soon sets in.

Allergies

If parasites and infections have been ruled out, your pet is likely to be suffering from allergies. Hypersensitivity reactions in which intense itching is a prominent symptom can be triggered by an allergen in pet food, insect bites, or the environment (such as dust, molds, pollen, etc.).

The nature of the allergic reaction can provide a clue as to the possible trigger of the dog’s allergy. Dogs with year-round itching may be suffering from an environmental allergy or food allergy. Seasonal itching is likely a hypersensitive reaction to seasonal allergens.

If a food allergy is suspected, your vet may perform a food trial. During a food trial, your pet will be given a new diet that does not contain the usual ingredients of his pet food. The new diet usually has a meat-based protein source(s) that the dog hasn’t eaten before. Your dog must strictly be given the specified diet for a particular length of time as instructed by your vet. No other foods should pass into the dog’s mouth while he is on the food trial.

Atopic dermatitis is a common allergic skin condition in dogs that causes chronic itching. The overall quality of life in dogs with atopic dermatitis is reduced without treatment. Intense itching could cause significant psychological burdens and could increase stress levels. According to a study, dogs with atopic dermatitis tend to develop more frequent problem behaviors. This could suggest that there is a possibility of a link between how severe the itching is and the psychological stress that the dog suffers from.

Antigen testing and intradermal skin testing can also be performed when trying to establish antigen exposure patterns. These tests, however, are not effective in identifying whether your pet’s problem may be caused by a food allergy.

Dry Skin

The extreme cold and dry air during winter can make a dog’s skin dry and itchy. If your pet swims in the pool during summer, his skin may react to the pool chemicals and may cause intense itching. Some pet shampoos and soaps may contain ingredients that can cause skin dryness.

Read more:

Allergy Tests for Dogs

Pet First Aid: How to Treat Minor Wounds

Allergic Ear Infections (Allergic Otitis) in Dogs

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